Enclosure gasket materials for environmental sealing include EPDM, TPE, silicone, and fluorosilicone. Each of these materials has advantages and disadvantages. By comparing your application requirements to a gasket material’s performance properties and costs, you can make the right choice for enclosure sealing and insulation. Partnering with a value-added manufacturer who can help you with compound selection also strengthens your product designs.
In this article from Elasto Proxy, the second in a series about enclosure sealing, you’ll take a closer look at these four types of materials for enclosure gaskets.
Enclosure Gasket Materials: EPDM Enclosure Gaskets
Ethylene propylene diene monomer (EPDM) is an enclosure gasket material that resists sunlight, ozone, abrasion, cutting, and tearing. This odor-free, color-stable, synthetic elastomer also resists water and weather. It has a high heat tolerance, too. Additional advantages of EPDM gaskets include good-to-high tensile strength and elasticity. Most EPDM has a durometer, or hardness, of 40 to 90 (Shore A).
EPDM enclosure gaskets have many desirable properties, but EPDM offers unsatisfactory resistance to gasoline, diesel fuel, motor oil, and freon. EPDM is economical, but it’s not recyclable. Applications for EPDM gaskets include the door seals on military vehicles and mobile equipment. Grades of EPDM that are flame retardant or food safe may be required for mass transit or food processing, respectively.
Enclosure Gasket Materials: TPE Enclosure Gaskets
Thermoplastic elastomers (TPE) are a group of rubber-like materials that combine the processing strengths of thermoplastics with the best qualities of thermoset rubbers. Known also as thermoplastic rubber (TPR), TPE is flexible, color-stable, weather-resistant, and resistant to cold temperatures. Consequently, TPE enclosure gaskets are replacing EPDM in some outdoor applications.
TPE is fully recyclable, but it’s more expensive than EPDM. During gasket fabrication and use, there may be issues with bendability in the corners. Because of their higher material costs, TPEs might not be the best choice for some high-volume runs. By sourcing TPE enclosure gasket materials in low-to-medium volume quantities, however, you can get the custom gaskets that you need.
Silicone Enclosure Gaskets
Silicones are a group of synthetic elastomers with good thermal stability and low chemical reactivity. They come in a range of durometers and colors, have consistent properties at high and low temperatures, and offer good insulation and excellent gas permeability. Importantly, silicone enclosure gaskets repel water, resist moisture, and form watertight seals.
Like EPDM rubber, silicone provides excellent resistance to ozone and sunlight but is not recommended for use with acids, alkalis, solvents, oil, or gasoline. Both types of enclosure gasket materials come in flame retardant and food safe grades. Unlike EPDM, however, silicone has low tensile strength and lacks strong resistance to abrasion and tearing. Medical applications are common for silicone gaskets.
Enclosure Gasket Materials: Fluorosilicone Enclosure Gaskets
Fluorosilicone enclosure gaskets combine the best properties of silicone with enhanced chemical resistance. They have good dielectric properties and resist high and low temperatures, ozone, sunlight, weather and aging. Fluorosilicones also resist oxidizing chemicals, chlorinated solvents, aliphatic and aromatic fluorocarbons, and animal and vegetable oils.
Like silicones, fluorosilicones can be filled with metal or metal-coated particles that impart electrical conductivity and shielding against electromagnetic interference (EMI). Fluorosilicones have less tensile strength and abrasion resistance than EPDM, too. Fluorosilicone gaskets are relatively expensive because of their material costs but are a good choice for applications such as pharmaceutical tableting.
Custom Enclosure Gaskets from Elasto Proxy
Do you need custom enclosure gaskets for environmental sealing? Whether you’re designing a lighting fixture, a toolbox, an electronic enclosure, or the door for a mobile equipment cabin, Elasto Proxy offers design assistance, help with material selection, expert fabrication, and value-added manufacturing services. To discuss your sealing application with one of our solutions providers, please contact us.
